DSA anodes

Fig. 9. Dow diaphragm cell, section view a, perforated steel back plate b, cathode pocket c, asbestos diaphragm d, DSA anode e, copper back plate f,...

Data, for a 32% caustic concentration at 90°C and a current efficiency of 96.0%, obtained in laboratory cells using a DSA anode and an activated cathode, where the membrane is against the anode at a 3-mm gap. 

Fig. 16. Performance data obtained ia laboratory cells using Nafion NX-961, DSA anode, activated cathode, narrow gap, at 90°C. Energy consumption is...

Chlora.tes. Sodium chlorate is produced by the electrolysis of sodium chloride at pH 6.5—7.5 in a one-compartment cell. DSA anodes and steel cathodes are generally used in chlorate cells. The electrolysis products, hypochlorous acid, and hypochlorite ions, react chemically to produce chlorate (eq. 

It is clearly important to know the different electrocatalytic behaviors of some potential DS A anodes and it is also important to obtain the influences of some incorporated elements on the properties of the resulting oxides coatings of DSA anodes. This present chapter focuses on our research related to electrochemical degradation of model substrates - phenol by the Sn02 anode and rare-earth doping Sn02 electrode, including fabrication electrodes, analysis method, and the evaluation of the characteristics of the electrodes. 

TABLE 26.9 Typical Voltage Distribution in a Membrane Cell at 5 kA/m2, 90°C, 34 Weight % NaOH, DSA Anode, 200 g/L NaClAnolyte, and Activated Cathode... 

Figure 4. Membrane cell voltage profile for Nafion 120 membrane. Key , 25% NaOH O, 32% NaOH A, 33% NaOH 0,35% NaOH. Conditions 85-90° C, 18-24% NaCl Anolyte DSA anode, Ni cathode, Vs inch electrode-membrane gap.

A typical mercury cell is shown in Figs 3.3 and 3.4. It consists of a large, shallow trough, dimensions 15 m x 2 m x 0.3 m, with a steel base which slopes slightly from end to end so that the mercury can flow along the bottom of the cell. The coated, expanded titanium DSA anodes (see Fig. 3.1), each of approximate dimensions 30 cm X 30 cm, enter the cell from the top and are arranged parallel to the mercury surface with an anode-cathode gap of about 1 cm. The cell will have about 250... 

The photographs show a Diamond Shamrock MDC 55 cell. It is designed on the toast rack principle where a number of DSA anodes are bolted to the cell base (Fig. 3.8(a)) and the cathode assembly (Fig. 3.8(b)) is designed so that each anode is totally surrounded by cathode when it is lifted into place. It is dropped down from above over the fixed anodes. The cell is then completed (Fig. 3.9) by attachment of electrical connections, electrolyte feeds and product take-off pipes. The cathode assembly shown in Fig. 3.8(b) has seventeen cathode tubes which extend from one side of the cell body to the other. The body of each tube (see Fig. 3.10) and the internal faces of the cell sides are constructed from steel mesh (maybe covered by nickel cathode catalyst) and the asbestos-based diaphragjm is deposited onto the mesh by dipping the whole cathode assembly into an asbestos slurry. The caustic soda and hydrogen are collected from inside the tubes. The MDC 55 cell produces approximately 5 tons of CI2 per day and has the dimensions 3 m X 1.6 m X 2 m. Its dry weight is almost 7 tons. 

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